May rainfall over much of the province was double the long-term average, soaking soils, slowing grass growth and making access around farms more typical of the end of winter than the start.
However, farmers report they have plenty of feed on hand and stock went into winter in excellent condition.
Local farmer Iain Bathgate said winter had arrived early after a very wet May, one of the wettest months in many years.
The Taieri was particularly wet.
With little drying, he said every new rainfall would add to the sodden soil.
Further south, Warepa farmer Mike Elliot said ground conditions resembled mid-winter rather than the start.
"May really was not a nice month. It has put us back a bit," the South Otago farmer said.
He was selling some beef cattle he had intended to take through winter to ensure he had enough feed for those that remained, and steers went on crops 10 days earlier because of the damage they were doing to pasture.
Some farmers were killing stock earlier than planned and he had heard of dairy farmers drying off herds early.
Mr Elliot said given the generally favourable spring, summer and autumn, farmers should have plenty of supplements on hand.
In North Otago, conditions were also pleasant after a favourable March and April, but rains last month made it a messy start for dairy graziers.
North Otago Federated Farmers president Ross Ewing said farms had plenty of cover and a dry summer meant some dryland farms were down on stock numbers.
Most farmers were comfortable but it was natural to want a late start to winter.
"You always like it to arrive a month later," he said.
The National Institute of Water and Atmospheric Research (Niwa) data show just how quickly the cold weather has arrived, with nationally May temperatures between 2degC and 2.5degC below average in many areas.
The West Coast was the only South Island region to have higher than average sunshine hours in May.
Snow arrived on the Central Otago mountain tops heavier and earlier than usual, but Hawea farmer Richard Burdon said it had caused few problems as farmers had plenty of feed and stock were in good health.
Mr Burdon said Central Otago farmers had noticed a slowing in demand for winter feed from dairy farmers as their cashflows tightened.
FarmRight farm investment manager Tony Cleland said such was the abundance of winter grazing in Southland that he had room for 2000 extra cows.
Delays in negotiating grazing contracts meant prices this year were $5-$10 a head lower than last year at between $20-$25 a cow a week.
He understood there was still quite a lot of unsold grain still in storage.
PGG Wrightson dairy manager Paul Edwards said such had been the oversupply of grazing that many farmers had bought other classes of animals to consume it, such as cull cows, heifers, steers and lambs.